Hydraulic actuated clamshell bucket attachment for stick clam excavators or the like



G. w.' MORK ET /-L 3,517,960

3 Sheets-Sheet l `lune 30, 1970 HYDRAULIC ACTUATED CLAMSHELL BUCKET ATTACHMENT FOR STICK @LAM ExcAvAToRs 0R THE LIKE Filed Feb. 2. 196e INVENTORS GEORGE W, MORK CARL F. NOVTNY BY ATTORNEY June 30, 1970 G, w. MORK ET AL HYDRAULIC ACTUATED GLAMSHELL BUCKET ATTACHMENT FOR STICK CLAM EXCAVATORS OR THE LIKE '5 Sheets-Sheet Filed Feb. 2. 1968 K s R R O O M T NW E V E N G I R CARL F. NOVOTNY ATToRNEv June 30, 1970 G, wl MQRK ETAL 3,517,960

HYDRAULIC ACTUATED CLAMSHELL BUCKET ATTACHMENT FOR STICK CLAM EXCAVATORS OR THE LIKE 3 Sheets-Sheet 5 Filed Feb. 2. 1968 a En Illlllllll IIIIIIIII KV. N Smm R GMW Il NWN y rr. VEF NG IRM. a OLA 3 GC ..44. Vl l nD 3 AT TORNEY United States Patent O m HYDRAULIC ACTUATED CLAMSHELL BUCKET ATTACHMENT FOR STICK CLAM EXCAVATORS R THE LIKE George W. Mork, South Milwaukee, and Carl F. Novotny, Milwaukee, Wis., assignors to Bucyrus-Erie Company, South Milwaukee, Wis., a corporation of Delaware Filed Feb. 2, 1968, Ser. No. 702,728

Int. Cl. B66c 3/02 U.S. Cl. 294-70 3 Claims ABSTRACT OF THE DISCLOSURE A hydraulic clamshell bucket attachment includes a hydraulic cylinder with a tubular cross head housing attached to its rod end and a rod with its outer end operating in the housing. Bucket halves with curved bottom walls are pivotal on a common axis at the outer end of the housing, and a cross head attached to the end of the rod and extending outwardly through slots in the housing has thrust links connecting its ends to respective bucket halves. The rod has an enlarged ange near the cross head which engages the housing to help take side loads. There is a floating seal between the rod and the cylinder casing; and the seal includes an outer ring fixed to the casing that is spaced from the rod and defines a groove facing the rod, and an inner ring sealed around the rod and received in the groove. There is a seal between the bottom surface of the inner ring and the bottom wall of the groove, and the inner ring is of smaller diameter than the groove to allow limited relative lateral movement. A tubular housing extension and a rod extension which can readily be connected between, respectively, the cylinder casing and housing and the rod and cross head are provided to allow the bucket attachment to be lengthened.

BACKGROUND OF THE INVENTION This invention relates primarily, but is not limited to, clamshell excavating machines of the type known as stick clams in which a bucket attachment is connected directly to the end of a live stick or boom so that the stick can be used to force the bucket downwardly into the material being excavated. Such machines are quite useful, for example, in digging holes and trenches, especially in hard ground.

A bucket attachment for a machine of the stick clam type must fulfill several requirements. For one thing, the actuating mechanism for the bucket halves Imust be powerful enough to operate even under the additional load imposed by the stick. Further, the attachment must be capable of accommodating eccentric loads occurring, for example, -when the machine is digging in uneven ground. Still further, it is desirable to be able to shorten or lengthen the attachment for digging deep holes or for reaching over obstacles.

SUMMARY OF THE INVENTION It is the general object of this invention to provide an improved, hydraulically actuated bucket attachment for machines of the general type contemplated herein.

It is one specific object of the invention to provide a hydraulically actuated bucket attachment which is powerful enough to operate under heavy loads.

Another specific object is to provide an attachment in which the bucket halves have a common pivot axis and bottom walls which are appropriately curved from front to rear to .minimize crowding of the material in the bucket as it is closed.

A further specific object is to have a hydraulic bucket attachment in which there is a bearing ange on an 3,517 ,960. Patented June 30, 1970 actuating rod which is engageable with a tubular housing to help take side thrust loads.

A further speciiic object lies in having a floating seal between an actuating rod and cylinder casing. This insures, among other things, that side thrust loads can be taken by the bearing flange on the rod.

`Still another specific object is to provide an attachment in which the length of the attachment can easily be varied simply by inserting or removing a housing extension and a rod extension.

The invention contemplates accomplishment of all of the foregoing and other objects, while still providing a bucket attachment that is relatively simple and inexpensive, of great mechanical strength, and relatively easy to manufacture, assemble and maintain.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a somewhat schematic side view in elevation of a stick clam excavator including a bucket attachment constructed according to the invention,

FIG. 2 is an enlarged fragmentary side View in elevation of the bucket attachment seen in FIG. 1, v

FIG. 3 is an enlarged fragmentary end view in elevation, with parts shown in cross section and alternative positions of certain elements in broken lines, further illustrating the attachment of FIGS. l and 2,

FIG. 4 is an enlarged fragmentary side view in cross section generally similar to FIG. 2, but showing the attachment with housing and rod extensions in place, and

FIG. 5 is an enlarged fragmentary view in perspective, with parts shown broken away and in cross section, illustrating the oating seal between the cylinder casing and rod of the bucket attachment.

DESCRIPTION OF THE PREFERRED EMBODIMENT The excavating machine of FIG. l is essentially a conventional back hoe type of excavator which has been modified by the addition of a bucket attachment into a stick clam excavator. The construction and operation of such machines and their modification in this manner is well known to those skilled in the art, and will not be discussed in detail herein. The basic machine includes a working frame 1 that is revolvably mounted on a crawler base 2. A boom 3 is pivotally footed on the frame 1 and is raised or lowered in a vertical plane by means of a pair of parallel hydraulic hoist cylinders 4, only one of which can be seen in FIG. l. A handle or stick 5 is pivotally mounted at the tip of the boom 3 and is pivoted in the same vertical plane by means of a hydraulic dig cylinder 6. When the machine is operated as a back hoe, a scoop-type bucket (not shown) is pivotally attached to the end of the stick 5, and is pivoted by means of a hydraulic wrist cylinder (also not shown) mounted on the stick 5. As shown herein, however, the bucket and wrist cylinder have been replaced by the clamshell bucket attachment which will now be described. One showing of a similar machine equipped as a back hoe excavator can be -found in the copending application of George W. Mork, Ser. No. 683,202, filed Nov. l5, 1967 now Pat. No. 3,463,336.

The bucket attachment comprises a double acting hydraulic cylinder indicated generally by the reference numeral 7, the base or casing end of which is attached, through a support bracket arrangement to be described, to the outer end of the stick 5 by means of a transverse pin 8, so that the entire bucket attachment is relatively freely pivotal in the same vertical plane as the boom 3 and stick 5. In addition to this major pivotal movement, it is desirable that the attachment be capable of limited pivotal movement in a plane transverse to the plane of movement of the stick and boom, this being primarily to allow compensation for-uneven groundconditions encountered during digging. To this end,` in the embodiment shown and as'can jbe seen-most clearly in FIG'.-2, the supporting connection between'thecylinder i',7w-*2'1nd-fstick 5 includes a first 'bracket 9*.that is lactuallyyconne'cted; to the pin 8 and includes downwardly .depending -plates i9', and a second bracket `that includes-upwardly extending arms 10 that are'receivedzbetweenthe'plates 9': The plates 9' are provided withopenings (not. shown), and the arms 10' haverocker lugs (not shown)received in the openings so that the bracketl'is supported from :the bracket 9 --and is'capable oflimite-d `transverse pivotal movement withv respect' theretoL"The actual rocker connection is not shown in detail herein, but is fully shown and described in the copendi'ng application of George W. Mork, Ser. N0. 702,708, filed' Feb. 2', 1968, now U.S. Pat. No. 3,462,029, to which reference'may be had. Although thisrocker ltype of vconnection is particularly preferred, it is not-absolutely essential to the' `invention herein, and other connections could be substituted, for example a two-pin universal connection of the type shown in U.S. Pat. No. 2,755,946, issued July 24, 1956 to I. I. Bevan, so long as there is some suitable connection between the casing end of the cylinder 7 and the tip of the stick 5.

It is also desirable in a stick clam excavator that the lbucket be capable of rotation about a vertical axis generally corresponding to the longitudinal axis of the attachment as seen in FIG. 1 to provide what is termed a swivel action. This is accomplished in the embodiment shown by having the cylinder casing proper, which is indicated by the reference numeral 11, rotatably mounted on the second bracket 10 by means of an appropriate swivel connection 12, which may be of any of the several types known to those skilled in the art and, therefore, is shown only schematically herein. Rotation of the casing 11, and therefore all the parts below it, is accomplished, through suitable known circuitry, by means of a conventional hydraulic motor 13 which is mounted on the second bracket 10 between the arms 10.

The outer or rod end of the cylinder casing 11 is provided with a radial connecting flange 14, and a tubular cross head housing 15 is provided at its inner end with a radial connecting flange 16 which faces the flange 14. Bolts 17 passing through the flanges 16 and 14 removably connect the housing 15 to the casing 11. The housing 15 is provided with opposite, parallel longitudinal slots 18 which extend along the major portion of its length but terminate short of its ends. Reinforcing plates y19 are preferably provided around the slots 18 to give the housing 15 a double thickness in this area.

As can be seen most clearly in FIG. 3, a piston 20- is movable in the cylinder casing 11, and an extensible and retractable piston rod 21 is disposed and operable in the housing 15. Near its outer end, which is in the housing 15, the rod 21 has a radial bearing flange 22 which has a relatively close sliding lit in the tubular housing 15; vExy tending from the bottom surface of the'ange 22 is an integrally formed clevis 23. A bar-shaped cross head v24 is received at about between vthe arms of the clevis and is removably connected thereto by means 'of a removable transverse pin -25' passing through suitable apertures in the clevis 23v and crossv head 24'. The cr'oss head 24 'extends outwardly on both sides of the housing'15 through thesiorsls. -f y The bottom 'end of the housing 1S provided 'with another radial connecting tlange 26, aridy a bucketzsupport bracket 27 is provided witha connectingiiange'surface 28 which faces the ang'eu26'. Bolts29 throughthe yiianges 26 and 28 yremovably"co nnect ,file bracketlZl'Z thefcross l headhousing 15. y l. v A pair of generally,conventional,bucket halves 30 are piVotallycQnnected to the bracke t.27 by .pins 31 which are at opposite ends of ther bracket, butv are inline so thatthetwo :bucket halves y30 Ah ave a commonpivotal axis. The bottom walls 30 of the vvbucket halves 30 are curved from front to rear (from left to right or right to leftqasV the bucketuhalves V30 'are seen in-FIG. 3), with the radius of curvature beingsubstantially the same as the radius of .closure ofthe bucket, or in other words with the center' ofwcur-vature being substantially coincident with the .axis definedby the pins 31.

.-Each bucket half 30 is provided with a transverse pin 32 -which extends across its entire width, the pinsv 32 being spaced onopposite'sides of the housing 15 and the axis dened by the pins 31. A thrust link designated generally by the reference numeral 33 is provided for each bucket half 30; and each link 33 includes a tubular quill portion 34 which rotatably receives .the corresponding pin 32, converging arms 35 leading upwardlyfrom the quill 34, and a clevis 36 at the ymeeting ends of the arms 35. Each clevis 36 receives a respective end of the cross head 24 and is removably and pivotally connected thereto by .means of va removable transverse pin 37 which passes through suitable aperture therein.

In FIG. 3, the piston rod 21 is shown in its fully extended position in which the cross head 24 is near the bottom of the slots 18 and the other end of the housing 15, the bucket halves 30` then being closed or together as shown in full lines. Retraction of the rod 21 will of course cause the cross head 24 to be raised which will, through the links 33, result in the bucket halves 30 being opened and moved to the position shown in dotted lines in FIG. 3. Subsequent re-extension of the rod 21 will then cause bucket halves 30 to close once again. The stick 5, and the boom 3, can of course be operated in the usual manner to force the bucket attachment downwardly as the halves 30 are being closed.

Having the two Ibucket halves 30 pivotal on the common axis defined by the pins 31 and having appropriately curved bottom walls .30" is quite helpful in insuring eiective operation, since it prevents or minimizes crowding of material as the bucket is closed. That is, if the two bucket halves vwould have laterally spaced pivotal axes as in many prior bucket constructions there is a tend- `ency lfor the available space to decrease as the bucket halves are closed, resulting in crowding of the material in the bucket. This same effect can result if the bottom walls of the bucket halves are not curved to match the radius of closure. Crowding presents a special problem in the case of a stick clam where the bucket may be required to close while the stick is exerting a relatively heavy downward force. While in the embodiment shown -the bottom walls 30' are flat from side to side and are curved only from front to rear, a spherical bottom Wall .configuration in which there is also a side to side curvature or other alternative configurations could be substituted.

When the machine is diggingin uneven ground, it is entirely possible that one bucket half 30l or one side of the bucket as a whole will hit the ground before the other, or will engage a rock or stone or be on somewhat lharder ground. In any of these cases, there is a tendency for the rod 21 to be moved laterally in one ydirection or.v the other and this can result in a substantial side load, especially when an Vadditional force is being exerted by the stick 5. Such loads are taken in the embodiment shown 'by the bearingv flange 22, which engages It iscommon for the rod of a hydraulic cylinder to have a seal interposed between it and the rod end of the cylinder::casing'that-allows substantially no lateral movement of theurodgdat least without impairing the operation ,.of--lthe seal.. Withsucha conventional construction, the seal could ine-effect interfere with'the function of the bearing flange 22;-and piston 20 intaking'the side lo'ads. Accordingly,=and for general eicien'cy, the attachment of this invention includes a special floating seal which is illustrated most clearly in FIG. 5. This seal includes a rigid circular outer ring member 38 which is generally L- shaped in cross section and is fixed to the casing 11 at its rod end, an O-ring 39 disposed in a groove 40l in the ring 38 being interposed between the ring 38 and the inner wall of the casing 11 to insure an effective seal. The inner edge of the end of the casing 11 is stepped at 41, and the ring member 38 has at its bottom end a radial flange 42 which is received in the stepped portion 41 to hold the ring 38 against upward movement. A split retainer ring 43 received in a notch in the stepped portion 41 engages the underside of the flange 42, the purpose of the retainer 43 being primarily to hold the ring 38 and its associated elements in place when the housing is disconnected as will be described below. The primary upward holding force for the ring 38 comes from an upwardly extending shoulder 44 formed in the housing 15 which is received in the stepped portion 41 and tight against the ring 43.

A washer-shaped cover 45 is secured to the ring member 38 by means of bolts 46, the member 38 and cover 45 together constituting a rigid outer ring which surrounds and is substantially spaced from the piston rod 21 and is fixed to the cylinder casing 11; and which denes a groove 47 of generally square cross section which has upper and lower walls and surrounds and faces the rod 21.

A rigid circular inner ring member 48 is disposed in the groove 47 and is fitted relatively closely about the piston rod 21. Both the upper and the lower edges of the inner surface of the ring 48 are cut away to define an upper annular recess 49 and a lower annular recess `50. A conventional flexible U-cup seal 51 is received in the upper recess 49 and is fitted tightly about the rod 21 to serve in usual fashion as the primary oil seal. An increase in pressure within the cylinder casing 11 will of course cause the cup seal 51 to expand to be more tight against the rod 21. Disposed within the lower recess 50 is a flexible wiper 52 which engages the rod 21 to keep it clean and prevent dirt from enteringthe casing 11.

The inner nng 48 has a relatively tight vertical fit in the groove 47, and an O-ring 53 seated in a groove 54 provided on the bottom surface of the ring 48 bears against the lower wall of the groove 47 and serves as a seal which prevents fiuid from. passing therebetween. The outer diameter of the ring 48, however, is substantially less than the diameter of the groove 47 so that there is a substantial gap therebetween. This, with the spacing of the outer ring from the rod 21, means that he piston rod 21 is capable of relatively substantially lateral movement in any direction with respect to the casing 11. This is accomplished without affecting the operation of the sealing ring 53 and without moving the rod 21 hard against the primary seal 51 to impair its effectiveness. The freedom of the rod 21 to move laterally in the area of its seal with the casing 11 insures, as indicated above, that the piston and casing 11 insures, as indicated above, that the piston 20 and flange 22 will take side loads which might occur during digging in uneven ground.

The hydraulic connections and circuitry for the cylinder 7, as well as the cylinders 4 and 6, have not been shown for the sake of simplicity. Various arrangements are possible, however, and are well known to those skilled in the art.

The bucket attachment of FIGS. 1-3 and 5 is fully functional as shown. In some cases, however, especially for digging holes or reaching over obstacles such as fences, it is desirable to be able to have a longer bucket attachment. To this end, the bucket attachment of this invention has been constructed to allow it to be easily extended to greater length. The extension elements are illustrated in FIG. 4, which is a view in cross section in the same orientation as FIG. 2. In the attachment as shown in FIG. 4, however, a tubular housing extension 55 has been interposed between the cylinder casing 11 and the cross head housing 15,'the extension 55 being provided with an upper radial connecting flange 56 which is connected to the casing fiange 14 by the bolts 17 and a lower raidal connecting flange 57 which is connected to the casing flange 16 by means of additional bolts 58. The upper end of the extension 55 is provided with a projecting shoulder 59 corresponding to the shoulder 44 of the housing 15, and the lower end of the extension 55 is suitably recessed to receive the shoulder 44.

In the attachment bf FIG. 4, there is also a piston rod extension v60, which is interposed between the piston rod 21 and the cross head 24. The extension 60 includes an upwardly extending apertured lug 61 received in the clevis 23 and connected thereto by the pin 25, a lower bearing flange 62 which corresponds to the flange 22, andan apertured clevis 63 which corresponds to the clevis 23 and receives the cross head 24 and is connected thereto by means of an additional pin 64.

To add or insert the housing extension 55 and rod extension 60, it is necessary only to remove the pins 37, extend the rod 21, remove the pin 25 (a suitable access opening 65 being provided in the housing 15 for this purpose), remove the bolts 17 and separate the elements. The rod extension 60 and housing extension 55 are then connected to the rod 21 and casing 11, the housing 15 and cross head 24 are connected to them, and finally the pins 37 are reinserted. Removal of the extension elements requires generally a reversal of these steps.

With the extension elements 55, 60 in place, the attachment is substantially lengthened. It will be oibvious that it could easily be further lengthened, however, simply by inserting additional rod extensions 60 and housing extensions 55.

The bucket attachment shown and described herein accomplishes all of the requirements for bucket attachments for a stick clam previously discussed. The hydraulic construction is quite powerful and easily adaptable to large machines which operate under heavy oads. The common Ipivotal axis of the bucket halves and their curved bottom wall configuration prevent crowding, thus further insuring satisfactory operation under great loads. Side thrust, which can be a serious problem under heavy loads, is adequately taken by the special bearing flange 22 and the piston 20, and the effectiveness of this arrangement is insured by the floating seal illustrated in FIG. 5, which also generally provides an improved seal. The length of the attachment may easily be altered by means of the extension members 55 and 60.

Although a preferred embodiment of the invention has been shown and described herein, it will be obvious that modifications in both structure and use are possible without departure from the spirit of the invention. The invention is not limited to use in stick clams, and a bucket attachment of this type might be useful in various other types of machines. Further, it is not necessary that the attachment include conventional dirt excavating bucket halves, and other forms of grabs might be used for different jobs. The oating seal of FIG. 5, although it is particularly designed to enhance the effectiveness of the bearing flange 22, Would as previously indicated be useful in any situation where it is desired to provide for lateral movement of the piston rod without interference by the seal. Various possible structural changes will be obvious to those skilled in the art; for example the several clevis arrangements could be reversed by, for example, putting the bifurcated clevis proper on the cross head 24 and having a lug on the rod 21 which is received therein.

In view of the many possible modifications, it is not intended that the invention be limited by the showing herein, the specific language of the following claims, or in any other manner, except insofar as is clearly required.

What is claimed is:

1. In a bucket attachment for stick clam excavators or the like, the combination comprising: a hydraulic cylinder having a casing end adapted to be attached to the stick of an excavating machine; a tubular cross head housing of circular cross section attached to the rod end of the cylinder, said housing being provided with opposite longitudinal slots therethrough; an extensible and retractable rod for the cylinder which has an outer end movable longitudinally in the housing, the rod being provided near its outer end with a circular radial bearing flange which has a relatively close t in the housing to be adapted to take side loads; an elongated cross head connected to the outer end of the rod that extends outwardly through the slots to present ends on opposite sides of the housing; a pair of bucket halves having pivotal con nections with the outer end of the housing; and thrust links connecting the ends of the cross head to respective bucket halves.

2. The combination of claim 1 wherein there is a seal between the rod and the rod end of the casing, which seal comprises: a rigid outer ring fixed to the casing which surrounds and is substantially spaced from the rod and defines a circular groove that faces and surrounds the rod and that has upper and lower walls; and a rigid inner ring which sealingly surrounds the rod and is received in the groove, there being a seal means between one of the upper and lower walls of the groove and the inner ring, the outer diameter of the inner ring being substantially less than the diameter of the groove to allow relative lateral movement between the inner and outer rings.

3. In a bucket attachment for stick clam excavators or the like, the combinaion comprising: a hydraulic cylinder having an inner casing end adapted to be attached to the stick of an excavating machine; a tubular housing having an inner end facing the casing and an outer end, the housing having opposite longitudinal slots therethrough, the outer end of the casing and the inner end of the housing being provided with radial connecting flanges that are adapted to face one another and be removably connected together; a tubular housing extension removably interposed between the outer end of the casing and the inner end of the housing, the extension having radial connecting anges at both ends that face and are removably connected, respectively, to the connecting flanges on the housing and causing; an elongated cross head in the housing that extends outwardly through the slots to present ends on opposite sides of the housing; an extensible an retractable rod for the cylinder which extends from the casing toward the housing, the outer end of the rod being provided with a clevis which is adapted to receive the cross head and be connected thereto by means of a removable pin; a rod extension removably interposed between the outer end of the rod and the cross head, the extension being provided at its inner end with a lug which is received by the rod clevis and connected thereto by means of a removable pin, and being provided at its outer end with a clevis which receives the cross head and is connected thereto by means of a removable pin; a pair of bucket halves having pivotal connections with the outer end of the housing; and thrust links connecting the ends of the cross head to respective bucket halves.

1/ 1963 Great Britain. 3/ 1964 Great Britain.

GERALD M. FORLENZA, Primary Examiner G. F. ABRAHAM, Assistant Examiner U.S. Cl. X.R.

mg? UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTIGN Patent No. 3, 517, 960 Dated June 30, 1970 Inventor(s) George W. Mork and Carl F. Novotny It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 4, line 21, "aperture" should read apertures Column 4, line 24, "other" should read outer Column 5, line 49, 1'1r1e" should read the Column 6, line 4, "radal" should read radial Column '7, line 33, "combnaion" should read combination Column 8, line 7, "causing" should read casing Column 8, line 10, "an'1 should read and SEP i9 1970 SEAI Attest:

Edward M.. Fletcher, Ir.

Commissioner of Patents 

